runtime error 2448 you cant assign a value to this object - ms-access

Question

I am using David-W-Fenton's answer to this question to try to allow users to print a report when they click on a control, but I am getting the following error message:
runtime error 2448: you cannot assign a value to this object.
The line of code triggering the error is:
Me.txtPageTo.Value = numPages
Here is the full code of the OnLoad event handler for the form:
Private Sub Form_Load()
Dim varPrinter As Printer
Dim strRowsource As String
Dim strReport As String
If Len(Me.OpenArgs) > 0 Then
strReport = Me.OpenArgs
Me.Tag = strReport
For Each varPrinter In Application.Printers
strRowsource = strRowsource & "; " & varPrinter.DeviceName
Next varPrinter
Me!cmbPrinter.RowSource = Mid(strRowsource, 3)
' first check to see that the report is still open
If (1 = SysCmd(acSysCmdGetObjectState, acReport, strReport)) Then
With Reports(strReport).Printer
Me!cmbPrinter = .DeviceName
Me!optLayout = .Orientation
End With
Dim numPages As String
numPages = Reports(strReport).Pages
Debug.Print "numPages = " & numPages
TypeName(Me.txtPageTo) 'added this line as a test after
Me.txtPageTo.Value = numPages
End If
End If
End Sub
numPages prints out to equal 0 just before the error is thrown, even though the report should have at least one page. Also, the error does not get thrown when the form is already open. The error only gets thrown when the form has to be opened. (Probably because the offending code is in the onload event.)
When I added TypeName(Me.txtPageTo) , it triggered runtime error 2424: The expression you entered has a field, control, or property name that mydatabasename cant find.
I think the problem is that I need to set the control source for txtPageFrom and txtPageTo. But how do I do that? This form will only be loaded by a vba method that is trying to print a report, so the values for txtPageFrom and txtPageTo will come from the calling method, not from some underlying data table. (there is no underlying data table for this dialog form.)
cmbPrinter and optLayout seem to be populating correctly using the code above.
Can anyone show me how to get past the error messages so that the form loads properly?
CORRECT, COMPLETE ANSWER:
The answer to this problem was to greatly simplify the code. The code in the link at the top of this posting is WAY TOO COMPLEX, and tries to reinvent things that are already done well by the tools built into Access and VBA. I was able to print reports without any of the complicated solutions by simply using the following code in the on-click event of a control on a form associated with the report:
Private Sub txtPrintReport_Click()
On Error GoTo Error_Handler
Dim commNum As Long
commNum = Me.CommunicationNumber
Dim strReport As String
Dim strVarName As String
strReport = "rptCommunicationFormForPrinting"
strVarName = "CommunicationNumber"
DoCmd.OpenReport strReport, acViewPreview, , strVarName & " = " & commNum, acWindowNormal, acHidden
DoCmd.RunCommand acCmdPrint
DoCmd.Close acReport, strReport
Exit_Point:
Exit Sub
Error_Handler: 'this handles the case where user clicks cancel button
If Err.Number <> 2501 Then
MsgBox Err.Description, _
vbExclamation, "Error " & Err.Number
End If
DoCmd.Close acReport, strReport
End Sub
That is all the code that was required. Much less than the link at the start of this question. And also much less than the answer below. I am marking John Bingham's answer as the accepted answer because he clearly worked a lot on this, and I am very grateful for that. But I ended up solving the problem with A LOT LESS CODE. My solution does not require the custom dialog form because it uses the Windows print dialog form. As such, the on load event code in my posting (taken from the link above), is not necessary.

Answer 1

The code posted cannot work, because when a form is opened as a dialog:
DoCmd.OpenForm "dlgPrinter", , , , , acDialog, strReport
no other logic after this line is executed until the form has been closed, at which point control returns to the next line after this one, and logic continues on - except of course you can no longer reference anything in that form, because it is now closed.
Ok, now there is a question, where is the button the user clicks to print a report?
What I'm thinking is to split the logic in PrintReport into two methods, one that launches it, and tells the form to configure itself (doing the stuff suggested in the comment), but the rest of PrintReport then needs to happen after the user clicks OK (or Cancel);
So if I assume that you've got a form which can launch one or more reports, and the button is on this form, what I would suggest is this:
In the click event for that button - no changes to what you've got.
In that buttons form, add this:
Public Sub DialogAccept()
With Forms!dlgPrinter
If .Tag <> "Cancel" Then
Set Reports(strReport).Printer = Application.Printers((!cmbPrinter))
Reports(strReport).Printer.Orientation = !optLayout
Application.Echo False
DoCmd.SelectObject acReport, strReport
DoCmd.PrintOut acPages, !txtPageFrom, !txtPageTo
PrintReport = True
End If
End With
DoCmd.Close acForm, "dlgPrinter"
DoCmd.Close acReport, strReport
Application.Echo True
End Sub
Change PrintReport to:
Public Function PrintReport(strReport As String, strVarName As String, numVal As Long) As Boolean
' open report in PREVIEW mode but HIDDEN
DoCmd.OpenReport strReport, acViewPreview, , strVarName & " = " & numVal, acHidden
'DoCmd.OpenReport strReport, acViewPreview, , , acHidden
' open the dialog form to let the user choose printing options
DoCmd.OpenForm "dlgPrinter", , , , , , strReport
Forms!dlgPrinter.Configure
End Function
In the OK/Cancel button click events on dlgPrinter put (after existing code, but removing any instances of "Docmd.close"):
Forms!Calling_Form_Name.DialogAccept
This then calls that method, to do the stuff that is meant to happen after the user says "I'm done with the dialog".
Finally add the configure method to dlgPrinter:
Public Sub Configure()
With Reports(Me.Tag).Printer
Me!cmbPrinter = .DeviceName
Me!optLayout = .Orientation
End With
Dim numPages As String
numPages = Reports(Me.Tag).Pages
Debug.Print "numPages = " & numPages
TypeName(Me.txtPageTo) 'added this line as a test after
Me.txtPageTo.Value = numPages
End Sub
And remove this code section from Form_Load.
Hoep this helps.
Lastly, if the form on which the button launching dlgPrinter can vary, change this line:
DoCmd.OpenForm "dlgPrinter", , , , , acDialog, strReport
to:
DoCmd.OpenForm "dlgPrinter", , , , , acDialog, strReport & ";" & me.Name
In form_load of dlgPrinter, break up me.Openargs using left() & mid() with instr(), and save me.Name into the tag of something on the form (which you're not already using the tag of).
In the OK/Cancel button click events, change the code above to:
Forms(Object.Tag).DialogAccept